I don't know much about Lync and Outlook. We are currently using an Exchange 2010 server, and are slowly migrating to Office 365 (we'll be using that server and cloud based exchange soon).
We have installed Skype for Business on the PCs, and they work fine with our Office 365 Lync server, but the Mac is having an issue. I am using Yosemite 10.10.4 and Lync 2011 (14.1.1).
It connects to Lync just fine, but as soon as I log in, I get the prompt:
Credentials are required
Type your user name and password to connect fro retrieving calendar data from Outlook.
It prompts over and over again. I am not sure how to get it to work. Because the Lync Office 365 server is in the cloud, I cannot type domainname\username in the user ID box. I can only use myname@mydomain.com.
Also, previously our UPN suffix used to be @mydomain.local, and might still be, but I can't log in with that either. And I don't know if this is causing an issue as well.
I'm kind of stumped, and am not sure what else I should do.
I also bumped the NTLM authentication to the top in the list of EWS Authentication in IIS, but it didn't seem to make a change. We have the latest rollup for Exchange 2010.